Occult occultations, computed
Location

Jupiter's moons in September 2026

Io · Europa · Ganymede · Callisto — 43 mutual events

Jupiter's four big moons put on a show every night: they slip behind the planet and into its shadow, cross its face, and drag their shadows across the cloud tops. Any telescope shows it. This is a mutual-event season — the moons' orbits are edge-on to the Sun and they eclipse and occult each other. Pick your place: the calendar and the nights keep only what your sky shows.

Where the moons are

Jupiter · September 2026

Jupiter's equator horizontal, east to the left as in binoculars. Drag through the month, or tap any event below to jump there; full screen (⤢) steps through a single night a minute at a time. Moons behind the planet fade, a moon in Jupiter's shadow is an empty ring, and a shadow on the disc is placed from the listed times. Positions ±0.1 Jupiter radii — for the picture; the times come from JPL.

Events

21 events you can see from New Delhi this month, on 16 nights

Mon
Tue
Wed
Thu
Fri
Sat
Sun
1
2
3
4
5
61718192102
11
12
131
14
151161172181
19
20
211
22
23
24
251262272281291
30
behind the planetin its shadowcrossing its faceshadow on the planetmoons eclipse or hide each otherGreat Red Spot mid-disc

Times in IST, when the moon's centre crosses the edge — as almanacs list them. A night runs from noon to noon. Tap an event to see it in the diagram.

Night of Sun 6 Sep

  1. Europa's shadow crosses Jupiter
    02:06 enters → 04:58 leaves · 2 h 52 min
    Jupiter below the horizon

Night of Mon 7 Sep

  1. Ganymede crosses Jupiter
    01:48 enters → 05:26 leaves · 3 h 38 min
    Jupiter below the horizon

Night of Tue 8 Sep

  1. Io occults Europa
    05:18 · 4.2 min
    71% of Europa covered · ≈0.4 mag fainter · Jupiter 21° up · dusk

Night of Wed 9 Sep

  1. Great Red Spot crosses the middle of Jupiter
    04:46 · on view 03:56–05:36
    Jupiter 14° up · dark sky
  2. Io in Jupiter's shadow
    05:01 disappears → reappears unseen · 2 h 17 min
    Jupiter 18° up · dark sky

Night of Thu 10 Sep

  1. Io's shadow crosses Jupiter
    02:24 enters → 04:40 leaves · 2 h 16 min
    Jupiter below the horizon
  2. Io crosses Jupiter
    03:03 enters → 05:21 leaves · 2 h 18 min
    Jupiter below the horizon

Night of Sun 13 Sep

  1. Europa's shadow crosses Jupiter
    04:40 enters → 07:33 leaves · 2 h 53 min
    Jupiter 16° up · dark sky

Night of Tue 15 Sep

  1. Europa behind Jupiter
    disappears unseen → 04:13 reappears · 2 h 54 min
    Jupiter 11° up · dark sky

Night of Wed 16 Sep

  1. Great Red Spot crosses the middle of Jupiter
    05:35 · on view 04:45–06:25
    Jupiter 30° up · dusk

Night of Thu 17 Sep

  1. Io's shadow crosses Jupiter
    04:18 enters → 06:34 leaves · 2 h 16 min
    Jupiter 14° up · dark sky
  2. Io crosses Jupiter
    05:03 enters → 07:21 leaves · 2 h 18 min
    Jupiter 23° up · dark sky

Night of Fri 18 Sep

  1. Io behind Jupiter
    disappears unseen → 04:30 reappears · 2 h 18 min
    Jupiter 17° up · dark sky

Night of Mon 21 Sep

  1. Great Red Spot crosses the middle of Jupiter
    04:44 · on view 03:54–05:34
    Jupiter 22° up · dark sky

Night of Fri 25 Sep

  1. Ganymede behind Jupiter
    disappears unseen → 04:14 reappears · 3 h 40 min
    Jupiter 18° up · dark sky

Night of Sat 26 Sep

  1. Io crosses Jupiter
    01:32 enters → 03:50 leaves · 2 h 18 min
    Jupiter below the horizon
  2. Great Red Spot crosses the middle of Jupiter
    03:54 · on view 03:04–04:44
    Jupiter 14° up · dark sky

Night of Sun 27 Sep

  1. Europa occults Callisto
    03:58 · 7.0 min
    38% of Callisto covered · ≈0.2 mag fainter · Jupiter 16° up · dark sky
  2. Europa eclipses Io
    04:38 · 4.6 min
    47% of Io covered · ≈0.7 mag fainter · Jupiter 25° up · dark sky

Night of Mon 28 Sep

  1. Great Red Spot crosses the middle of Jupiter
    05:33 · on view 04:43–06:23
    Jupiter 37° up · dusk

Night of Tue 29 Sep

  1. Europa in Jupiter's shadow
    04:57 disappears → reappears unseen · 2 h 52 min
    Jupiter 30° up · dark sky

Reading the list

Times are for the moment the moon's centre crosses the edge of Jupiter or of its shadow, the convention of published tables; the moon's own disc takes a few minutes to cross. A start or end marked unseen happens behind Jupiter or inside its shadow. “Only what I can see” keeps events with Jupiter more than 10° up in a dark sky. Positions are from JPL DE431 and the jup365 satellite ephemeris, Jupiter as an oblate spheroid with its shadow cone. Mutual-event brightness drops assume uniform discs and are estimates. Events are geocentric — the same instant everywhere on Earth to well under a second. The Great Red Spot is a storm, not ephemeris: its times are when it crosses the middle of the disc (the central meridian, System II from DE431), taking its longitude as 91° on 1 Jun 2026 drifting 1.75° a month (Sky & Telescope, from the JUPOS drift record). Each degree that estimate is off moves the time by 1.65 min; the spot is well placed for about 50 minutes either side.